Triumph Repair: Valve clearances affect compression, valve clearances, valve clearance

Question
Sir,
Please may you advise: does the setting of tappets/valve clearances affect the compression generated within a cylinder? If so, why? And would an overly tight setting create a high or low compression reading?
many thanks
Alan - Africa  

Answer
Hi Allen, I guess technicaly you could get a lower reading but it would be because the valve was'nt closing all the way. that would be WAY out of adjustment. no chance of a higher reading. I don't know all the in's and out's of changing the valve clearance from the spec of the particular engine in other words it is'nt something you play around with to change the performance of the engine. I do know if you are not sure that the adjustment is right you want to have them a little looser than tighter. if the are too tight they don't seat long enough to let heat flow away into the seat and can burn the valve. that will give low compression 100% of the time. if you need more help i'm here. Dave